1: 100 percent / 1N aq. HCl / methanol / 20 h / 0 °C 2: 88 percent / NEt3 / CH2Cl2 / 0.33 h / 0 °C 3: 99 percent / imidazole / dimethylformamide / 23 h / 0 °C 4: 96 percent / diisobutylaluminium hydride / diethyl ether; hexane / 0.75 h / -80 °C 5: 71 percent / CrO3, pyridine / CH2Cl2 / 0.33 h / 10 °C 6: 87 percent / NEt3 / CH2Cl2 / 48 h / Ambient temperature 7: 1. n-butyllithium / 1. -20 deg C, THF, hexane 2. a. -80 deg C, b. warm up to -10 deg C, 75 min c. 90 min, -10 deg C 8: 68 percent / aq. oxalic acid / tetrahydrofuran / 1 h / Ambient temperature 9: 86 percent / K2CO3 / 1 h / 23 °C 10: 13.5 mg / tetrabutylammonium fluoride / tetrahydrofuran / 25 h / 20 °C 11: aq. NaOH / methanol / 5 h / Ambient temperature View Scheme